Automatic stabilization system for hydrofoil craft

ABSTRACT

A system comprising a sensor unit serving to control hydraulic cylinders which actuate the control surfaces of foils and incorporating automatic interlocking means assuring safe operation of the craft. The automatic interlocking means comprise an electronic relay with adjustable setting and locking mechanisms for setting the control surfaces of foils into the neutral positions should the craft exceed the maximum preset angles of deviation.

States Korotkov et a1.

[ 1 May 28, 1974 1 AUTOMATIC STABILIZATION SYSTEM FOR HYDROFOIL CRAFT [22] Filed: Aug. 16, 1972 [21] Appl. No.: 281,013

52 us. (:1. 114/665 111, 114/126, 244/77 1= 51 1m. 01 663 1/28 58 Field ofSearch ..114/66.5 H, 126, 144 R,

114/144 A; 244/77 F, 77 D, 42 D, 42 DA; 318/584-586, 588

8/1964 Schertel 114/665 H 3,149,601 9/1964 3,156,209 11/1964 3,191,567 6/1965 3,213,818 10/1965 Barkley 114/665 H FOREIGN PATENTS OR APPLICATIONS 1,411,242 1965 France 114/665 H Primary Examiner-George E. A. Halvosa Assistant Examiner-Edward R. Kazenske Attorney, Agent, or Firm-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A system comprising a sensor unit serving to control hydraulic cylinders which actuate the control surfaces of foils and incorporating automatic interlocking means assuring safe operation of the craft.

The automatic interlocking means comprise an [56] Referen Cit d electronic relay with adjustable setting and locking UNITED STATES PATENTS mechanisms for setting the control surfaces of foils 1 800 365 4/1931 S 4/126 into the neutral positions should the craft exceed the perry 1 3,130,702 4/1964 Fischer 114 665 H maxlmum preset angles of 3,137,260 6/1964 Harris et a1, l14/66.5 H 3 Claims, 3 Drawing Figures 0 .1. .1L LOCKING I "9 MECHANISM SE S N 0R CONTROL UNIT 02 VALVE b FEED BACK TRANSMITTER .47

' PATENTEUMAY 28 I974 SHEU 2 [IF 2 AUTOMATIC STABILIZATION SYSTEM FOR HYDROFOIL CRAFT The present invention relates to shipbuilding, and more specifically to the equipment for hydrofoil craft.

The invention may be used to advantage in the best way on hydrofoil craft with a foil system which assures crafts self-stability with respect to the controllable elements of attitude at cruising speed.

In known craft the self-stability of movement is ensured by using shallowly submerged and surface piercing hydrofoils acted upon by hydrodynamic forces. Should the craft lose her stability due to the effect of a perturbation as from waves, a stability moment comes into play due to the action of these forces with the result that the crafts stability is restored as soon as the perturbation ceases to exist.

Coming under the category of ships with such hydrofoil system are the Denison (U.S.A.); ships of the RT type (Switzerland) including RT-SO hydrofoils and the Kometa" (U.S.S.R.) which enjoy wide-spread application.

Unlike fully submerged hydrofoils which assure better seaworthiness and habitability, but fail to provide for adequate self-stability (primarily due to the height in foilborne condition and heeling angles, craft of the above type do not require systems for the automatic control of lift. The use of automatic stabilization systems in stable hydrofoil craft permits to substantially improve habitability and comfort by reducing oscillation and overloads in fully arisen sea; in calm weather and slight sea the automatic stabilization system is deenergized, the control surfaces set into the neutral position with respect to the foil chord, and the crafts attitude and stability are maintained by means of her own foil system.

Known in the art are automatic stabilization systems for stable hydrofoil craft, such as an electronic system used in the Denison (US. Pat. No. 3,191,567, Cl. 1 14-665 The system comprises a sensor unit with gyroscopic sensors, electronic amplifiers, hydraulic actuators and is used to control the flaps of foils, each actuator incorporating means of monitoring the position of the flap and a circuit for setting the flap into neutral manually.

Known in the art are also automatic stabilization systems for fully submerged hydrofoils (US. Pat. Nos. 3,137,260 and 3,l56,209, Cl. 114-665) which can also be used for craft with stable hydrofoil system.

At present preference is given to automatic stabilization systems for fully submerged hydrofoils comprising, as a rule, gyroscope sensors electronic amplifiers and actuators in the form of hydraulic drives which control the lift of hydrofoils by varying the angle of incidence of foil and the position of flaps or by supplying a stream of air to the upper and lower surfaces of the lifting hydrofoil and to the strut surface.

A difficulty preventing the use of automatic stabilization systems in stable hydrofoil craft is the fact that adequate operational safety of stabilized craft cannot be secured with simple single-channel arrangements so that emergency situations, such as deep and sharp heelings, are likely to occur in the event of breakdowns or malfunctionings of the system leading to abrupt moving and jamming of control surfaces.

On the other hand, automatic stabilization systems designed on more reliable lines for fully submerged hydrofoils incorporate a multitude of foil-safe arrangements, such as sectionalized control surfaces each operated by independent controls and sensors, stand-by devices, self-monitoring facilities and the like make the system a very sophisticated one with a great number of components and add to the cost as compared with stable craft dispensed with stabilization systems.

The above-mentioned steps aimed at increasing the reliability fail to guarantee trouble-free operation of the system so that in all known systems provision is made for disabling the automatic stabilization and changing over to manual control during the transition into the hullbome condition and for the manual setting of control surfaces to the neutral or initial position by means of stabilization system actuators.

Said measures do not completely eliminate the possibility of emergency situations should the automatic stabilization system fail to operate at cruising speed.

It is an object of the present invention to provide an automatic stabilization system for a hydrofoil craft employing a simple single-channel layout (sensor unitamplifier-actuator-control surface of foil) which assures safe operation of the craft under positive control of her heel and trim.

This object is accomplished by the provision of an automatic heeling and trim angle stabilization system for hydrofoil craft comprising a sensor unit which controls by means of amplifier units the operation of hydraulic cylinders intended to move the control surfaces of foils.

In accordance with the invention, located at the output of the sensor unit there is an automatic interlocking means connected to hydraulic cylinders, said means sets the control surfaces of foils to the neutral position with respect to their chords should the heel and trim exceed a preset limit and then locks the surfaces in this position and interlocks the automatic stabilization system.

This embodiment permits to prevent heels and trims of a magnitude which might result in an emergency situation for the craft in the case of failures in the automatic stabilization system employing the single-channel layout, and to continue under conditions of stable movement on locking the control surfaces of foils mechanically.

It is of advantage if said interlocking means comprise an electronic relay adjustable for maximum values of heeling and trim angles, said relay actuating control valves of a self-contained hydraulic system supplying hydraulic cylinders used to operate locking mechanisms linked with piston rods of the hydraulic cylinders.

This permits to effect the setting of the control surface of foil into the neutral position from any position at any instant during which the automatic stabilization system is in operation and enables mechanical locking of the latter at the same time.

Another embodiment of the invention contemplates the use of locking mechanisms each comprising a twolobe rotatable detent with the axis of rotation fixed with respect to the crafts hull, said detent being located in a profiled groove made in the piston rod of the hydraulic cylinder.

This permits to improve the design and to reduce the friction forces coming into play during the engagement and disengagement of the locking mechanism.

Such embodiment of the automatic stabilization system according to the invention provides for safe operation of a hydrofoil craft equipped with a simple singlechannel automatic stabilization system, improves seaworthiness of the craft and assures better habitability and comfort.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which:

FIG. I shows a schematic diagram of the automatic stabilization system according to the invention;

FIG. 2 shows an embodiment of the locking mechanism with a movable profiled wedge (longitudinal section);

FIG. 3 shows another embodiment of the locking mechanism with a two-lobe rotatable detent (longitudinal section).

For the purpose of the description, the automatic stabilization system shown in FIG. 1 depicts only one control surface of foil, which is a controllable flap.

A sensor unit 1 (FIG. 1) (comprising, by analogy with known circuits, a gyroscopic sensor of the crafts deviation angles and sensors of angular rates of these deviations) is connected to an electronic amplifier 2 which may consist of a number of functional amplifiers and which, in its turn, is connected to a hydraulic control valve 3 (an electrically-actuated slide valve).

The hydraulic control valve 3 communicates with a hydraulic system (not shown) and with spaces in a hydraulic cylinder 4 and a piston rod 4a of said cylinder actuates by means of a tie rod 4b a control surface of a foil 5, comprising a controllable flap 6 (the letter 8 in FIG. 1 indicates the deflection of the flap 6).

A feedback transmitter 7 is mechanically connected to the flap 6 and is electrically coupled to the input of the electronic amplifier 2.

Automatic interlocking means 8 is provided at the output of the sensor unit I and consists of an electronic relay 9 with a response setting 0, and a locking mechanism l actuated by means of a hydraulic cylinder 11 which is hydraulically connected to a hydraulic valve 12 of self-contained hydraulic system (not shown).

The locking mechanism shown in FIGS. 2 and 3 may be embodied in two ways.

FIG. 2 shows the first embodiment of said mechanism 10. It comprises a movable profiled wedge 13 displaceable in guides MM rigidly connected to the crafts hull 14, said wedge interacting with a profiled groove 15 made in the piston rod 4a of the hydraulic cylinder 4 of the flap 6.

In the embodiment shown in FIG. 3, the locking mechanism 10 consists of a two-lobe rotatable detent 16 with the axis of rotation 0, fixed with respect to the crafts hull 14, said detent being connected to the hydraulic cylinder 11 by means of a lever I7.

The rotatable detent 16 is located in a profiled groove 18 made in a piston rod 19 of the hydraulic cylinder 4 of the flap 6.

The profiled groove 15 (FIG. 2) or 18 (FIG. 3) may be made either in the piston rod 4a (or 19) of the hydraulic cylinder 4, or in an extension thereof rigidly attached thereto, e.g., in the tie rod 4b of the flap 6 (FIG. 2) or in an extension of the piston rod 19 (FIG. 3).

At the design stage, it is preferable to select the difference between the dimension a at the inlet side of the profiled groove 15 (FIG. 2) and the dimension b at the leading end of the profiled wedge 13 so that it somewhat exceeds the maximum deflection 6 of the controllable flap 6 as measured at the point where the locking mechanism is located, whereby the flap 6 can be set to the neutral position with respect to the chord L-L" from a position corresponding to any deflection angle 8.

The angle a of the profiled groove 18 (FIG. 3), in its turn, should provide for the setting of the locking detent 16 at any flap angle 6.

Where there are a plurality of controllable flaps 6, the number of electronic amplifiers; control valves 3, hydraulic cylinders 4 and locking mechanisms 10 with hydraulic cylinders 11 and valves 12 must be come spondingly increased.

The automatic stabilization system functions in the following manner.

The sensor unit 1 determines the crafts deviation from a predetermined position in terms of heel and trim, using the gyroscopic vertical as the reference.

These signals, on being fed to the amplifier 2 along with signals from the rest of sensors and the feedback transmitter, are shaped in accordance with the selected pattern of control into a resultant signal which puts over the controllable flap 6 of the foil 5.

The direction in which the flap 6 is being put over is determined mainly by the direction in which the craft deviates due to the perturbation in force and the rate at which the flap is being put over is controlled by the feedback transmitter 7 so as to vary directly with the magnitude of crafts deviation.

The control signal, as shaped by the amplifier 2, is fed to the hydraulic control valve 3, which opens its ports so as to admit hydraulic fluid into the space of the hydraulic cylinder 4 in proportion to the magnitude of this signal.

Acted upon by the pressure of the hydraulic fluid, the piston rod 40 of the hydraulic cylinder 4 is moved so as to put over the flap 6.

The feedback transmitter 7 constantly monitors the angle through which the flap 6 is being put over ensuring proportional relationship between this angle and the magnitude of the resultant control signal.

The hydrodynamic forces resulting from the deflection of the controllable flap 6 of the foil 5 create moments which stabilize crafts given attitude when underway with the automatic stabilization system in good repair.

Simultaneously with catering for the operation of the main channel, the electric signals from the sensor unit 1 are fed to the input of the electronic relay 9, which continuously compares them with the predetermined setting (0 corresponding to the craft's maximum devi ation in terms of heel and trim.

In the event of malfunctioning, false signals appear in the automatic stabilization system, bringing about jamming of the flap 6 or putting the fiap hard over at maximum rate with the result that the angles of crafts deviation by far exceed the values common for normal operation of the automatic stabilization system.

In this case the current signal 6 of the crafts deviation exceeds the setting (9 of the relay 9 so that the latter closes, energizing the electric relay actuated valve 12 to admit hydraulic fluid from the self-contained hydraulic system into the hydraulic cylinder 11. Said cylinder actuates the locking mechanism 10 which sets the flap 6 to the neutral position and locks it simultaneously.

If the locking mechanism 10 shown in FIG. 2 is used, the hydraulic cylinder 11 causes the profiled wedge 13 to move along the guides MM" and enter the groove 15 of the piston rod 40, thereby setting the flap 6 into the neutral position and locking it.

If the embodiment shown in FIG. 3 is given preference, the hydraulic cylinder 11 turns the two-lobe detent 16, by means of the lever 17 so as to engage the groove 18 in the piston rod 19 and to set the flap 6 into the neutral position; at the same time the detent assumes a position along the axis of the piston rod 19 and locks the flap in said position.

Simultaneously, the automatic stabilization system is deenergized and interlocked due to the action of the relay 9.

Any malfunctioning of the automatic stabilization system which results in crafts tolerable preset deviation, sets into operation the automatic interlocking means which position and lock the control surfaces of foils in the neutral position. The use of this system assures safe operation of the craft, since any failures in the stabilization system will not bring about heels and trims hazardous for passengers and for the craft itself.

The automatic stabilization system disclosed herein assures operational safety, simplicity of design and maintenance, low weight and cost.

What is claimed is:

l. A system for automatic stabilization of heeling and trim angles for a craft having hydrofoils with control surfaces, said system comprising a sensor unit; first hydraulic power cylinders connected via amplifier units to said sensor unit and said first hydraulic power cylinders serving to move the control surfaces of said hydrofoils of said craft; automatic interlocking means provided at the output of said sensor unit and connected to said hydraulic cylinders, said means setting said control surfaces of the hydrofoils to the neutral position as measured with respect to the chord thereof upon the crafts deviation in terms of heel and trim beyond a predetermined limit with subsequent locking of said surfaces in said position and interlocking of the automatic stabilization system, said interlocking means comprising an electronic relay with an adjustable setting for maximum heeling and trim angles, said relay actuating hydraulic valves of a self-contained hydraulic system supplying second hydraulic cylinders to actuate locking mechanisms interacting with piston rods of the first hydraulic cylinders.

2. A system according to claim ll, wherein each locking mechanism comprises a movable profiled wedge displaceable in guides rigidly connected to the crafts hull, said wedge interacting with a profiled groove made in the piston rod of the first hydraulic cylinder of the control surface of the hydrofoil.

3. A system according to claim 1, wherein each locking mechanism comprises a two-lobe rotatable detent having an axis of rotation fixed with respect to the crafts hull, said detent being located in a profiled groove made in the piston rod of the first hydraulic cylinder. 

1. A system for automatic stabilization of heeling and trim angles for a craft having hydrofoils with control surfaces, said system comprising a sensor unit; first hydraulic power cylinders connected via amplifier units to said sensor unit and said first hydraulic power cylinders serving to move the control surfaces of said hydrofoils of said craft; automatic interlocking means provided at the output of said sensor unit and connected to said hydraulic cylinders, said means setting said control surfaces of the hydrofoils to the neutral position as measured with respect to the chord thereof upon the craft''s deviation in terms of heel and trim beyond a predetermined limit with subsequent locking of said surfaces in said position and interlocking of the automatic stabilization system, said interlocking means comprising an electronic relay with an adjustable setting for maximum heeling and trim angles, said relay actuating hydraulic valves of a selfcontained hydraulic system supplying second hydraulic cylinders to actuate locking mechanisms interacting with piston rods of the first hydraulic cylinders.
 2. A system according to claim 1, wherein each locking mechanism comprises a movable profiled wedge displaceable in guides rigidly connected to the craft''s hull, said wedge interacting with a profiled groove made in the piston rod of the first hydraulic cylinder of the control surface of the hydrofoil.
 3. A system according to claim 1, wherein each locking mechanism comprises a two-lobe rotatable detent having an axis of rotation fixed with respect to the craft''s hull, said detent being located in a profiled groove made in the piston rod of the first hydraulic cylinder. 